Dosing and monitoring

Intravenous dosing regimen

aPTT a	dose change
initially	80 unit/kg bolus, then 18 units/kg/hr
<1.2	80 unit/kg bolus, then increase by 4 units/kg/hr
1.2-1.5	80 unit/kg bolus, then increase by 2 units/kg/hr
1.5-2.3	no change
2.3-3.0	decrease rate by 2 units/kg/hr
>3.0	stop infusion for 1 hour, then decrease rate by 3 units/kg/hr

Why?

• It produces therapeutic levels or higher sooner than the standard method ^a without clearly affecting bleeding rates.
• Fewer recurrent deep vein thromboses occur. ^a

A weight-based regimen reduces recurrent deep vein thrombosis

Patient	Treatment	Comparison	Outcome	CER	RRR (95% CI)	NNT (95% CI)
requiring heparin therapy a	weight-based regimen	fixed dose regimen	aPTT ratio > 1.5 at 24 hours	77%	-25% (-46% to -7%)	5 (3 to 14)
			recurrent DVT	25%	80% (14% to 96%)	5 (3 to 27)